Components which are used at high temperatures, e.g. turbine blades or vanes in gas turbines, have active cooling, during which a coolant is introduced into the interior and runs through the turbine blade or vane through coolant ducts, and if appropriate emerges from film-cooling holes.
In this case, it is important that the turbine blade or vane is not cooled excessively, since this greatly increases the coolant consumption, which in turn would reduce the efficiency of the turbine because the cooling air is mostly taken from the compressor.
It is therefore important to set the coolant consumption by optimally setting the flow rate.